1. Field of the Invention
The present invention relates to a thermal printer. More particularly, the present invention relates to a thermal printer which includes an improved cable which connects a main board and a recording head to form an image on a print medium via heating.
2. Description of the Related Art
Generally, thermal printers print an image on a thermal imaging print medium by applying heat from a recording head to the print medium. The print medium provides a color image selected according to heating temperatures and duration. The print medium is different from paper, which is typically used as a print medium, and has a structure as illustrated in FIG. 1.
Referring to FIG. 1, the print medium includes a transparent substrate 1. A first image forming layer 2, a spacer 3, a second image forming layer 4, and an upper protection layer 5 are sequentially stacked on an upper surface of the transparent substrate 1. A third image forming layer 6, a reflection layer 7, and a lower protection layer 8 are sequentially stacked on a lower surface of the transparent substrate 1.
The first, second, and third image forming layers 2, 4, and 6, which produce different colors, are formed of yellow, magenta, and cyan leuco dyes, respectively, and a developer. The spacer 3 separates the first image forming layer 2 from the second image forming layer 4 and is transparent so that colors produced in the first and second forming layers 2 and 4 can be recognized when viewed from the upper protection layer 5 side adjacent to the second forming layer 4. The first, second, and third image forming layers 2, 4, and 6 represent colors which respond to different heating temperatures and duration.
To form an image on such a print medium, a conventional thermal printer having a structure as illustrated in FIG. 2 can be used.
Referring to FIG. 2, the conventional thermal printer includes a transfer unit 10 for transferring a print medium M, fixed first and second recording heads 21 and 25 disposed on both surfaces of the print medium M, respectively, and first and second support units 31 and 35 disposed to face the first and second recording heads 21 and 25, respectively. The first and second recording heads 21 and 25 are electrically connected to a main board 40 to receive power and image data from the main board 40.
As described above, in the conventional thermal printer which forms a color image on the print medium M using the two fixed recording heads 21 and 25, the recording heads 21 and 25 can be easily connected to the main board 40 using cables 41 and connectors 45. However, the use of the two recording heads 21 and 25 complicates the thermal printer structure and increases the costs for manufacturing the device.
Hence, there is a need for a thermal printer which forms an image on both surfaces of a print medium by using a single, movable recording medium. However, in this case, since the main board is most likely fixed, and the recording head is movable, cable connections can interfere with the transfer of the printing medium and the size of the thermal printer.
Accordingly, there is a need for improved cable connections that can be made without affecting the transfer of a print medium and the size of the thermal printer.